Make sure every one counts together on New Year's Eve at Midnight !
Nice and simple countdown that keeps everyone synchronized.
Have everyone raise his iPhone up in the darkness for the last 10 seconds so that there is a nice group effect of sound and color.

It produces a short sound regularly (every hour, then every 15 minutes, then every minute in the last five minute then every ten seconds in the last minute and finally the last 15 seconds).
The last sound is a luxury authentic crystal glass sound... like have a drink and cheers !

You can eat your 12 grapes in the last 12 seconds before midnight...

You can put your iPhone or iPod touch on a sound system while partying. It will be your main party countdown.

IMPORTANT : Beware that the power save mode is off during the countdown. If you launch it long before midnight (or the target date you have modified) then you should put your device on a power docking station.
Otherwise, it is nice to see all the iphone flashing in colors in the last 15 seconds before midnight without having the power saving mode turning your device off.